Question: Simplify the following expression: $9\sqrt{52}$.
Solution: First, try to factor a perfect square out of the radical. $= 9\sqrt{52}$ $= 9\sqrt{4 \cdot 13}$ Separate the radical and simplify. $= 9\sqrt{4} \cdot \sqrt{13}$ $= 9 \cdot 2 \cdot \sqrt{13}$ $= 18\sqrt{13}$